Method and system for purifying contaminated water

ABSTRACT

This disclosure concerns a system for purifying contaminated water and a method for using the system. More specifically, the invention concerns removing contaminants, such as those introduced by fracking, from a contaminated water.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of the earlier filing date of U.S.provisional patent application No. 62/882,970, filed on Aug. 5, 2019,which is incorporated herein by reference in its entirety.

ACKNOWLEDGMENT OF GOVERNMENT SUPPORT

This invention was made with government support under Award No.DE-AR0001000, awarded by the United States Department of Energy. Thegovernment has certain rights in the invention.

FIELD

This disclosure concerns a system and method for purifying fluids, suchas contaminated water, with certain disclosed embodiments specificallyconcerning purifying fracking wastewater.

BACKGROUND

The development of hydraulic fracturing technology (fracking) has aidedUnited States' energy security. One side effect of its rapid expansionhas been the production of vast quantities of highly toxic water, asmuch as 30,000 m³ per well from 1.7 million wells, as of 2015.Reinjecting this water in the well risks eventual seepage intofreshwater reservoirs and has raised major environmental and healthconcerns. Reliable data on the costs and energy consumption of thetreatment and disposal of this contaminated water are scarce.Notwithstanding the lack of reliable data, at least four major problemshave been identified for treating fracking water:

1. The variety of the chemicals: The composition of fracking wastewateris location-dependent and may contain a large and varying number andquantity of chemicals, many of which are absorbed underground. Currentwater treatment technologies focus on treatment of low-salinity andlow-toxicity water and removal of specific chemicals. They fail tohandle water with either a wide range or high concentration ofcontaminants.

2. Portability: About half of all fracking wastewater is produced in thefirst few weeks of a well's approximately 10-year life. Currentcontaminated water purification and desalination technologies aredesigned for massive stationary plants. It is cost-prohibitive to builda suitable treatment facility for only a few weeks of high throughput.

3. Energy consumption and cost: Today's most efficient purification anddesalination processes use 3-5 times the minimum required energy. Thatis greatly amplified when the water in question is of unknowncomposition, is toxic, and has very high total dissolved chemicals(TDC). In a cost-sensitive industry, handling this water candifferentiate an economical system and process from an uneconomical one.

4. Fouling: All membrane-based, as well as some thermal processes,involve contaminated water and/or saline water interacting with porousmaterials. By design, the solutes accumulate on the porous materials, bethey membranes or packed beds. A solution is needed that substantiallyeliminates interactions between contaminated water and high-surface areaporous materials to vastly decrease the rate of unwanted soluteaccumulation.

Tables 1 and 2 below illustrate the varied and complex composition oftypical fracking wastewater.

TABLE 1 Typical Composition of Fracking Fluid (Not Wastewater) CompoundAmount (%) Water 90.8 Sand 8.5 Acids 0.15 Clay stabilizers 0.12 Scaleinhibitors 0.09 Surfactants 0.075 Friction reducer 0.07 Breakers 0.06Biocides 0.06 Gels 0.05 pH balancing 0.01 Balance 0.015

TABLE 2 Most Common Chemicals in Fracking Wastewater Boiling DensityConcentration 5 Compound (° C.) (g/ml) days (ppm) TDS — — 94,000 Ammonia−33 0.77 70 Benzene 80 0.89 625 Toluene 110 0.88 833 Ethylene glycol 1971.11 29,700 2-Butoxy-ethanol 171 0.9 10,000 Other: Chlorides, sulfates,Chlorides + Na: Na, B, Sr, Ba, trace compounds 98,000

A variety of water desalination systems are commercially available.However, these systems are all solely intended for processing sea andbrackish water and are impractical for reclaiming fracking wastewaterfor the aforementioned reasons.

SUMMARY

Disclosed embodiments of the present system and process address thesechallenges by taking advantage of water contaminants, operating tightlyaround the water saturation point, and avoiding any membrane or packedbed. The disclosed invention is largely agnostic of the feedcontaminated water source and composition. Accordingly, an importantbeneficial feature of the present invention is that it can be used toprocess any contaminated water composition without regard tocomposition. Some or all contaminants in a particular contaminated watercomposition may form azeotropes.

Certain disclosed embodiments concern modular, portable, and scalabletechnology to extract clean water from any contaminated water, withhydraulic fracturing (fracking) wastewater being one particular example.Disclosed embodiments can utilize any heat source to drive the process,although certain particular embodiments use low-grade heat to reduce oreliminate the need for electrical power consumption, providing apurification process that operates less expensively than knownprocesses.

Certain disclosed embodiments use humidification-dehumidification in aswirling nozzle or nozzle-demister, combined with an in-line demister,to reclaim clean water or grey water from contaminated water. Theswirling nozzle or nozzle-demister may be thermally actuated to reducepower consumption and enable a more energy-efficient process. Disclosedembodiments take advantage of the properties and behavior of watercontaminants, as well as the thermodynamics of humid streams, toefficiently separate and condense water vapor.

One embodiment of a disclosed system comprises: an inlet to receive anaqueous composition comprising water and undesired materials, generallyreferred to herein as contaminated water, such as wastewater, with oneexample being fracking wastewater; a heat source configured to heat thecontaminated water to produce contaminated water vapor; anozzle-demister having a gas inlet configured to admit dry gas to thenozzle-demister; a contaminated water vapor inlet; and acondenser/separator, such as a heat exchanger or a demister. Thenozzle-demister typically also includes a clean water conduit forreceiving clean water from the clean water outlet, and a fluid wasteconduit for receiving fluid waste from a fluid waste outlet. The systemcan be configured, such that the gas inlet, the contaminated water vaporinlet, or both, are injected tangentially into the system to create aswirling fluid flow. Alternatively, or additionally, the nozzle demistermay further comprise a vortex generator to produce a rotating orswirling heated gas. The vortex generator may include one or morestationary or annular fins to induce swirl. A swirling motion also maybe induced before the flow enters the nozzle. Gas enters thenozzle-demister through a gas inlet port and flows past the vortexgenerator, which directs the gas into a fast-moving gas jet.Contaminated water can be supplied to the contaminated water tankthrough the contaminated water inlet or inlets. In certain embodiments,additional heat is added to the contaminated water to producecontaminated water vapor. The contaminated water vapor can be introducedto the nozzle demister through a contaminated water vapor inlet where itmixes with the fast-moving gas jet, yielding a humid stream of gas,water vapor, and waste vapor. In certain embodiments, the humid streamof gas, water vapor, and waste vapor can then be separated by acondenser/separator, such as a heat exchanger or demister, which causesthe water to condense out of the humid stream. Condensed water can thenbe collected at a clean water outlet and directed into the clean waterconduit. In certain embodiments, the remaining gas and waste vaporpasses through the system and is collected at a fluid waste outlet, fromwhich it flows into a fluid waste conduit.

Yet another disclosed aspect of the invention concerns a system forpurifying contaminated water, particularly fracking wastewater,comprising a thermally-actuated swirling nozzle or nozzle-demister.Generally, the system can include a contaminated water tank, at leastone contaminated water inlet, a thermally-actuated nozzle-demister, aclean water conduit, and a fluid waste conduit. In certain embodiments,gas enters the thermally-actuated nozzle-demister through a gas inletport. The gas can be heated, causing it to accelerate within thenozzle-demister. The gas flows past a vortex generator having one ormore stationary vanes, which direct the gas into a fast-moving gas jet.In some embodiments, contaminated water can be supplied to thecontaminated water tank through the contaminated water inlet or inlets.The contaminated water tank may have a sludge drain to facilitate theremoval of dense, solid wastes. Additional heat can be added to thecontaminated water to produce contaminated water vapor. The contaminatedwater vapor can be introduced to the thermally-actuated nozzle-demisterthrough a contaminated water vapor inlet and mixed with the fast-movinggas jet. In certain embodiments, the fast-moving gas jet with entrainedcontaminated water vapor flows into a converging nozzle thatconcentrates the flow of the fast-moving jet, increases the jet's speedand reduces its temperature. The temperature of the fast-moving gas jetwith entrained contaminated water vapor can be reduced to a temperaturebelow the saturation temperature of the gas to condense water vaporentrained in the gas, yielding a misty mixture of gas, waste vapor, andfine, condensed droplets of clean water. In certain embodiments, anin-line demister separates the fine, condensed droplets of clean waterfrom the mixture of gas and waste vapor. The condensed droplets arecollected at a clean water outlet and flow into a clean water conduit.In certain embodiments, the remaining mixture of gas and waste vaporflows through the in-line demister and into a diverging nozzle. In thediverging nozzle, the waste vapor may condense or partially condense,yielding a mixture of gas, gaseous waste, and liquid waste, which can becollected at a fluid waste outlet. The mixture of gas, gaseous waste,and liquid waste flow into a fluid waste conduit.

In certain embodiments, condensation heat from the condensation of waterdroplets in the converging nozzle can be recovered and transferred tothe contaminated water. This may be accomplished, for example, bypositioning a heat exchanger between one or more of the contaminatedwater inlets and the converging nozzle.

In certain embodiments, excess heat from the clean water and the fluidwaste can be recovered and transferred to the contaminated water in thecontaminated water tank. This may be accomplished, for example, bypositioning a heat exchanger between the clean water conduit and thecontaminated water tank and/or between the fluid waste conduit and thecontaminated water tank.

In certain embodiments, gas supplied to the nozzle-demister may be air,which may, at various sections of the system, also be dry. At varioussections of the system, the air may have a first velocity, V₁,approaching but greater than 0 m/s. At other sections of the system, theair may have a second velocity, V₂, greater than the V₁.

Contaminated water that may be processed using various disclosed systemembodiments and method for their use may have any of a variety ofcontaminants, in any and all combinations. Examples of typicalcontaminants include, without limitation, sand, acids, clay stabilizers,surfactants, ammonia, benzene, toluene, ethylene glycol,2-butoxy-ethanol, chlorides, sulfates, sodium, boron, strontium, barium,and any and all combinations thereof.

Other disclosed aspects of the invention concern a method for usingdisclosed embodiments of a contaminated water purification device. Onegeneralized embodiment of the method involves bringing hot, low-humiditygas into contact with contaminated water to form humid gas withentrained water vapor, waste vapor, and vaporized contaminants. Themethod can further involve accelerating the humid gas with entrainedvapors and imparting an angular velocity to enhance the mixing of thegas and vapors. In certain embodiments, the method can further involvereducing the temperature of the humid gas with entrained water vapor,waste vapor, and vaporized contaminants below the saturation temperatureof water to condense water from the humid gas, which can be collectedwhile leaving the gas and waste vapor behind.

Yet another disclosed aspect of the invention concerns a method forusing a disclosed water purification system comprising athermally-actuated swirling nozzle or nozzle-demister. The methodgenerally involves supplying contaminated water to a contaminated watertank through one or more contaminated water inlets. Gas having a firstvelocity is supplied to a nozzle-demister through a gas inlet andaccelerated to a second velocity greater than the first velocity. Incertain embodiments, the acceleration can be caused by heating the gaswithin the nozzle-demister. The accelerated gas is directed past avortex generator to produce a high-speed gas jet. In certainembodiments, the method may further involve supplying contaminated watervapor from the contaminated water tank to the nozzle-demister through acontaminated water vapor inlet. Contaminated water vapor can beentrained in the high-speed gas jet to yield a humid gas-contaminatedwater stream having entrained water and waste vapors. In certainembodiments, the method can further involve supplying the humidgas-contaminated water stream to a converging nozzle, which increasesthe velocity and decreases the temperature of the humid gas-contaminatedwater stream. Reducing the temperature of the gas-contaminated waterstream condenses clean water droplets, which may be separated from thegas and waste vapor in the humid stream with an inline-demister. Theseparated water droplets can then be collected at a clean water outletin the nozzle-demister and supplied to a clean water conduit. In certainembodiments, the method further involves supplying the remaining gas andwaste vapor stream to a diverging nozzle, which decreases the velocityof the gas and waste vapor stream and allows the waste vapor to condenseor partially condense. The mixture of gas, gaseous waste, and/or liquidwaste exits the nozzle-demister through a fluid waste outlet and passesto a fluid waste conduit.

In certain disclosed embodiments, the method further involvesrecapturing the heat from the condensation of the clean water dropletswithin the converging nozzle. This recaptured heat can be supplied tothe contaminated water in the contaminated water inlets. The method canalso further involve recapturing excess heat from the clean waterconduit and the fluid waste conduit. This heat can be supplied to thecontaminated water in the contaminated water tank.

In certain embodiments, the gas supplied to the nozzle-demister may beair, which may at various sections of the system also be dry. At varioussections of the system, the air may have a first velocity approaching 0m/s. At other sections of the apparatus, the air may have a secondvelocity greater than the first.

The foregoing and other objects, features, and advantages of theinvention will become more apparent from the following detaileddescription, which proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of a portable and modular contaminated watertreatment unit in accordance with the present disclosure at a frackingsite.

FIG. 2 is a flowchart illustrating a general contaminated watertreatment process in accordance with this disclosure.

FIG. 3 is a schematic illustrating one exemplary embodiment of acontaminated water treatment system in accordance with the presentdisclosure.

FIG. 4 is a perspective schematic showing a cross section of oneembodiment of a swirling nozzle demister in accordance with anembodiment of this disclosure.

FIG. 5 is a schematic showing various exemplary heat exchangers inaccordance with the present disclosure.

DETAILED DESCRIPTION

The following detailed description is provided with reference to thedrawings and embodiments described herein. The drawings are illustrativeand are not intended to limit the scope of the disclosure.

I. Definitions

The following explanations of terms and abbreviations are provided tobetter describe the present disclosure and to guide those of ordinaryskill in the art in the practice of the present disclosure. As usedherein, “comprising” means “including” and the singular forms “a” or“an” or “the” include plural references unless the context clearlydictates otherwise. The term “or” refers to a single element of statedalternative elements or a combination of two or more elements, unlessthe context clearly indicates otherwise.

Unless explained otherwise, all technical and scientific terms usedherein have the same meaning as commonly understood to one of ordinaryskill in the art to which this disclosure belongs. Although methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present disclosure, suitable methods andmaterials are described below. The materials, methods, and examples areillustrative only and not intended to be limiting. Other features of thedisclosure are apparent from the following detailed description and theclaims.

The disclosure of numerical ranges refers to each discrete point withinthe range, inclusive of endpoints, unless otherwise noted. Unlessotherwise indicated, all numbers expressing quantities of components,molecular weights, percentages, temperatures, times, and so forth, asused in the specification or claims are to be understood as beingmodified by the term “about.” Accordingly, unless otherwise implicitlyor explicitly indicated, or unless the context is properly understood bya person of ordinary skill in the art to have a more definitiveconstruction, the numerical parameters set forth are approximations thatmay depend on the desired properties sought and/or limits of detectionunder standard test conditions/methods as known to those of ordinaryskill in the art. When directly and explicitly distinguishingembodiments from discussed prior art, the embodiment numbers are notapproximates unless the word “about” is recited.

Azeotrope refers to a mixture of two liquids having a substantiallyconstant boiling point and composition during an evaporation process,such as distillation.

II. Introduction

Described herein are embodiments of a system for purifying contaminatedwater, particularly wastewater from a fracking process. Also disclosedherein are embodiments of a method for using the disclosed system.

FIG. 1 illustrates a portable and modular contaminated water treatmentunit in accordance with the present disclosure at a fracking site. Thefracking site includes fracking equipment 10 for performing a frackingprocess. A portable, modular contaminated water processing system 12according to the present disclosure can be positioned adjacent frackingequipment 10. Modular contaminated water processing system 12 includesplural water treatment modules 14, comprising plural processed waterstorage tanks 16. The fracking site also includes a wastewater pool 18.

FIG. 2 illustrates a generalized sequence for one disclosed embodimentof a method for purifying contaminated water, such as frackingwastewater. In a first process step 20, hot, low-humidity gas is broughtinto contact with contaminated water containing contaminants. Thelow-humidity gas absorbs contaminated water and contaminants in vaporform, yielding humid gas with water and waste vapor in process step 22.The humid gas enters a nozzle-demister in process step 24, which furthermixes the gas, water vapor, and waste vapor, and imparts angularvelocity. The temperature of the humid gas is reduced to condense watervapor into water droplets in step 26, which are rejected from the humidgas flow. Condensed clean water droplets are then collected in processstep 28, leaving the gas and contaminants within the nozzle-demister.

FIG. 3 illustrates one exemplary embodiment of a water purificationsystem 300 in accordance with the present disclosure. Dry, stagnant gas,typically air, having a first velocity V₁ near 0 m/s and a firsttemperature T₀, enters the water purification system 300 at gas inlet302 of nozzle-demister 304. The gas is then heated to a temperature T₁greater than T₀ by heat communicated through wall 306 of nozzle-demister304 and the heated gas reaches a second velocity V₂ greater than V₁.System 300 includes a vortex generator 308 to produce a rotatinghigh-speed gas jet from heated gas at temperature T₁ and velocity V₂. Aperson of ordinary skill in the art will appreciate that any structurecapable of producing a rotating gas can be useful as a vortex generator308, including a device having one or more stationary vanes or annularfins. Slow-moving contaminated water vapor from contaminated waterreservoir 330 enters the nozzle-demister 304 through contaminated watervapor inlet 310 and becomes entrained in the high-speed gas jet producedby vortex generator 308 to form a humid gas-contaminated water vaporstream having a third temperature T₃, a third velocity V₃, and asaturation temperature T₃-sat. System 300 includes one or more devicesto alter the properties, such as velocity and pressure, in the flowstream. For certain disclosed embodiments, the humid gas-contaminatedwater vapor stream accelerates through a device that adjusts pressureand velocity in the flow stream. Embodiments can include, for example, aconverging nozzle 312 to accelerate the flow to a fourth velocity V₄greater than V₃, during which enthalpy of the flow stream converts tokinetic energy. This reduces the temperature of the stream to a fourthtemperature T₄ less than T₃, where T₃ is below the saturationtemperature of the stream in that thermodynamic state. Disclosed systemsneed not have a converging nozzle 312 if flow stream velocity and/orpressure are adjusted upstream. In these embodiments nozzle 312 can bereplaced with a straight pipe. For the exemplary embodiment illustratedby FIG. 3, water condenses out of the humid gas-contaminated water vaporstream and creates a misty flow within converging nozzle 312.Condensation heat transfers from the misty flow within converging nozzle312 to contaminated water inlet 314 by contacting heat exchanger 316.Centrifugal forces push the condensed water droplets to a devicesuitable to dehumidify the flow stream and separate water. This processcan be achieved using a number of devices configured to condense andseparate water, such as conventional heat exchangers. One aspect ofcertain disclosed embodiments of the present invention is to controlthermodynamic properties of fluids, particularly temperature andpressure, in the system. For example, to obtain clean water using thesystem, the thermodynamic properties of contaminated water fluidscomprising water are adjusted to approach the dew point of water in thecomposition, which dew point depends on the actual composition of thefluid flow. And the composition of the contaminated water processed bythe system can vary over time. Accordingly, the composition of thecontaminated water can be monitored over time to adjust the physicalparameters of temperature and pressure to approach the dew point ofwater to condense substantially pure water from the contaminated waterstream. In the exemplary embodiment illustrated by FIG. 3, centrifugalforces push the condensed water droplets to the periphery of thenozzle-demister 304, where demister 318 extracts the water droplets fromthe misty flow. Condensed water droplets are collected at clean wateroutlet 320 and flow into clean water conduit 322 while the remaining gasand waste vapor stream passes through demister 318 and into divergingnozzle 324. System 300 also can include a second device to control flowproperties, such as velocity and pressure. Certain disclosed embodimentsinclude a diverging nozzle 324, where waste vapor is condensed to liquidwaste and is collected at waste outlet 326, where it flows into wasteconduit 328 for safe disposal. Alternatively, waste vapor can be routedto appropriate system locations and ignited to provide additional heatto the system. Contaminated water is supplied to the system throughcontaminated water inlet 314. Contaminated water in contaminated waterinlet 314 is heated at heat exchanger 316 by condensation heat fromconverging nozzle 312 before collecting in contaminated water reservoir330. Additional contaminated water may be supplied from contaminatedwater inlet 336. Contaminated water in reservoir 330 is heated toproduce contaminated water vapor. Heat energy needed to vaporize thecontaminated water can be supplied by heat rejected from clean waterconduit 322 and/or waste conduit 328, as well as by external heat source332. The vaporization of contaminated water within contaminated waterreservoir 330 may leave heavier waste products behind. The accumulationof such heavier waste products may be removed via sludge drain 334.

FIG. 4 illustrates an exemplary embodiment of a thermally-actuatednozzle-demister 400 having a gas intake end 402 and a gas outlet end404. Gas enters nozzle-demister 400 through gas intake end 402 and iswarmed by heat conducted through nozzle-demister wall 406. Vortexgenerator 408 is positioned near gas intake end 402 and directs gasentering the nozzle-demister 400 into a gas jet. Contaminated watervapor enters nozzle-demister 400 through waste vapor inlet 410, andmixes with the gas jet from vortex generator 408 to form a humid,gas-contaminated water vapor stream. Converging nozzle 412 is locateddownstream from waste vapor inlet 410 and has proximal end 414 anddistal end 416. The humid gas-contaminated water vapor stream entersconverging nozzle 412 at proximal end 414 increases in velocity anddecreases in temperature, thereby causing water droplets to condense asthe humid gas-contaminated water vapor stream approaches distal end 416.Heat from the condensation of the water droplets is transferred tocontaminated water inlet feed 418 at heat exchanger 420. In-linedemister 422 is located at distal end 416 of converging nozzle 412. Aswater condenses from the humid gas-contaminated water vapor stream,inline demister 422 causes water droplets to form and collect at cleanwater outlet 424, while gas and waste vapor pass through inline demister422 and into diverging nozzle 426. Diverging nozzle 426 is locateddownstream of in-line demister 422 and causes waste vapor entrained ingas flowing through demister 422 to condense into liquid waste, which iscollected at gas and waste outlet 428, located at gas outlet end 404 ofnozzle-demister 400.

FIG. 5 illustrates exemplary embodiments of heat exchangers inaccordance with the present disclosure and suitable for use inembodiments previously discussed. Heat exchanger 500 transfers heat fromthe humid gas-contaminated water vapor stream within the nozzle-demister502 to feed contaminated water supplied from contaminated water intake504 and may allow condensation heat from the condensation of waterdroplets to be recaptured. Heat exchanger 510 transfers heat fromcondensed, clean water in clean water conduit 512 to contaminated waterin contaminated water reservoir 530 and may reduce the additional heatthat must be supplied to vaporize the contaminated water. Heat exchanger520 transfers heat from condensed, fluid waste in waste conduit 522 tocontaminated water in contaminated water reservoir 530 and may reducethe additional heat that must be supplied to vaporize the contaminatedwater.

The following example is provided to illustrate certain aspects ofdisclosed embodiments for producing clean water. A person of ordinaryskill in the art will appreciate that the scope of the present inventionis not limited to the particular features of this example.

Example 1

In one example of a method for producing 1 kg of clean water by thepurification of contaminated water, 3 kg of dry air having a firstvelocity near 0 m/s and a first temperature of 25° C. enters the nozzledemister. Heat is supplied to the dry air, heating it to 85° C. andaccelerating it to 25 m/s as it passes a vortex generator that directsthe air into a high-speed air jet. 1.1 kg of contaminated water vapor ator near a saturation temperature of 109° C. and having a velocity near 0m/s is added to the high-speed air jet, yielding 4.1 kg of humidair-contaminated water vapor with a temperature of 95° C., a saturationtemperature of 90° C., and a velocity of 18 m/s. The humidair-contaminated water vapor passes into the convergence nozzle and thetemperature drops to 86° C. as the vapor accelerates, which is below thesaturation temperature of the humid air-contaminated water vapor. 1 kgof water condenses into droplets having a temperature of 86° C., thewater is removed from the humid air-contaminated water vapor by anin-line demister, and is collected at the clean water outlet. Cleanwater collected at the clean water outlet passes into the clean waterconduit at 86° C., and excess heat is rejected to the contaminated waterreservoir. Condensation heat is transferred from the convergence nozzleto feed contaminated water at 25° C., raising the feed contaminatedwater temperature before it is added to the contaminated waterreservoir. Remaining 3.1 kg of air-contaminated water vapor, having atemperature of 86° C. and a velocity of 148 m/s, passes through thein-line demister and into the divergence nozzle, where it heats to 97°C. and slows to a velocity of 10 m/s. Waste vapor begins to condenseinto liquid waste, and the mixture of air, gaseous waste, and liquidwaste is collected at the air and waste outlet. Excess heat from themixture of air, gaseous waste, and liquid waste is rejected to thecontaminated water reservoir.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrated embodiments are only preferred examples of the invention andshould not be taken as limiting the scope of the invention. Rather, thescope of the invention is defined by the following claims. We thereforeclaim as our invention all that comes within the scope and spirit ofthese claims.

We claim:
 1. A system for purifying contaminated water, comprising: acontaminated water reservoir to receive contaminated water through acontaminated water inlet; a heat source configured to heat thecontaminated water to produce a hot contaminated water vapor stream; anda nozzle-demister having a gas inlet configured to admit dry gas to thenozzle-demister, a contaminated water vapor inlet that receives thecontaminated water vapor stream from the contaminated water reservoir, acondenser/separator, a clean water outlet, and a fluid waste outlet. 2.The system according to claim 1 configured to process frackingwastewater.
 3. The system according to claim 1 where thecondenser/separator is a demister.
 4. The system of claim 1, wherein thenozzle-demister is a thermally actuated nozzle demister.
 5. The systemaccording to claim 1 wherein the dry gas, the contaminated water vapor,or both, are injected tangentially into the system to introduce fluidswirl.
 6. The system according to claim 1 wherein the nozzle demisterfurther comprises a vortex generator to produce a rotating heated gas.7. The system according to claim 1 wherein the nozzle-demistercomprises: the gas inlet configured to admit the dry gas to the nozzledemister; a heat exchange wall configured to transmit heat to gasadmitted through the gas inlet and to confine gas flow; a vortexgenerator configured to produce a high-speed gas jet from the gasadmitted to the nozzle demister; the contaminated water vapor inletconfigured to admit the hot contaminated water vapor stream to thenozzle-demister; a first device for adjusting pressure and/or velocityin the hot contaminated water vapor stream, the first device configuredto concentrate flow of the humid gas-contaminated water vapor stream andto cause water condensation; the demister and condenser configured tocollect water condensed from the humid gas-contaminated water stream,while permitting the remaining gas and waste vapor mixture to passthrough; the clean water outlet configured to permit clean, condensedwater from the nozzle-demister to flow to the clean water conduit; thefluid waste outlet configured to remove the gas, gaseous waste, andliquid waste from the nozzle demister.
 8. The system according to claim7, wherein: the first device for adjusting pressure and/or velocity influid flow is a converging nozzle configured to concentrate flow of thehot contaminated water vapor stream and to condense water; the seconddevice for adjusting pressure and/or velocity in fluid flow is adiverging nozzle; or both.
 9. The system according to claim 1 whereinthe nozzle demister is configured to provide a gaseous exhaust fluidlyrouted to a heating zone, wherein the gaseous exhaust is ignited toprovide heat for the system and to scrub unburned volatile compoundsfrom the exhaust.
 10. The system according to claim 1, wherein gasadmitted through the gas inlet is substantially dry air and the dry airis heated by the system.
 11. The system according to claim 1, furthercomprising a first heat exchanger, comprising: a feed contaminated waterinlet configured to receive low-temperature contaminated water; and aheat exchange region in contact with the converging nozzle of thenozzle-demister and configured to transfer heat from the hotcontaminated water vapor stream to the incoming contaminated water. 12.The system according to claim 11, further comprising: a second heatexchanger configured to transfer heat from a clean water conduit to thecontaminated water; a third heat exchanger configured to transfer heatfrom a fluid waste conduit to the contaminated water; or both.
 13. Thesystem according to claim 1, further comprising a sludge drainconfigured for removal of dense, solid waste from the contaminated waterhoused in the contaminated water reservoir.
 14. A method, comprising:providing a system according to claim 1; and operating the system topurify contaminated water.
 15. The method according to claim 14,comprising: supplying gas to the nozzle-demister through the gas inlet;accelerating the gas supplied to the nozzle demister and producing ahigh-speed gas jet; supplying the contaminated water vapor to thenozzle-demister; entraining the contaminated water vapor in a high-speedgas jet to create a humid gas-contaminated water stream; supplying thehumid gas-contaminated water stream to a converging nozzle to increasethe velocity and decrease a gas contaminated water stream temperature;condensing water out of the gas-contaminated water stream as thegas-contaminated water stream cools; supplying condensed water to aclean water conduit through a clean water outlet in the nozzle-demister;supplying a gas and waste vapor stream to a diverging nozzle to decreasevelocity of the gas and waste vapor stream to condense liquid waste;supplying the gas, gaseous waste, and/or liquid waste to a fluid wasteconduit; and collecting clean water and fluid waste from the process.16. The method according to claim 15 wherein the contaminated water isfracking wastewater.
 17. The method according to claim 16, wherein thewastewater contains, sand, acids, clay stabilizers, surfactants,ammonia, benzene, toluene, ethylene glycol, 2-butoxy-ethanol, chlorides,sulfates, sodium, boron, strontium, barium, or any combination thereof.18. The method according to claim 15 comprising using a vortex generatorto generate the high speed gas jet.
 19. The method according to claim15, wherein the gas admitted through the gas inlet is substantially dryair.
 20. The method according to claim 15, wherein the dry gas suppliedto the nozzle demister is accelerated by supplying heat energy.
 21. Themethod according to claim 15 wherein condensation heat from condensingwater out of the gas-contaminated water stream is transferred tocontaminated water in one or more contaminated water inlets.
 22. Themethod according to claim 15 wherein: heat from the clean water conduitis transferred to the contaminated water; heat from the fluid wasteconduit is transferred to the contaminated water; or both.
 23. Athermally-actuated nozzle-demister, comprising; a gas inlet configuredto admit a dry gas to the nozzle demister; a heat exchange wallconfigured to transmit heat to the gas admitted through the gas inlet; avortex generator configured to produce a high-speed gas jet from the gasadmitted to the nozzle demister; a contaminated water vapor inletconfigured to admit hot contaminated water vapor obtained from acontaminated water reservoir to the nozzle-demister; a converging nozzleconfigured to concentrate flow of a humid gas-contaminated water vaporstream and induce water condensation; an in-line demister and condenserconfigured to collect water condensed from the humid gas-contaminatedwater stream, and to permit the remaining gas and waste vapor mixture topass through; a clean water outlet configured to remove clean, condensedwater from the nozzle-demister; a diverging nozzle configured to slowgas and waste vapor flow and condense liquid waste from the waste vapor;and a gas and waste outlet configured to remove gas, gaseous waste, andliquid waste from the nozzle demister.
 24. A method, comprising:providing a thermally-actuated nozzle-demister according to claim 23;and operating the thermally-actuated nozzle-demister in a process forpurifying contaminated water.
 25. A system, comprising: contaminatedwater reservoir means; heat source means configured to heat contaminatedwater in the contaminated water reservoir means to produce contaminatedwater vapor; and nozzle-demister means for receiving contaminated watervapor from the contaminated water reservoir and for mixing thecontaminated water vapor with a carrier fluid.
 26. A system forpurifying contaminated water, comprising: a contaminated water inlet toreceive contaminated water; a heat source configured to heat thecontaminated water to produce a hot contaminated water vapor stream; anda nozzle-demister having (a) a gas inlet configured to admit dry gas tothe nozzle demister, (b) a heat exchange wall configured to transmitheat to gas admitted through the gas inlet and to confine gas flow, (c)a vortex generator configured to produce a high-speed gas jet from thegas admitted to the nozzle demister, (d) a contaminated water vaporinlet configured to admit the hot contaminated water vapor stream to thenozzle-demister, (e) a pressure and/or velocity adjustor to adjustpressure and/or velocity in the hot contaminated water vapor stream, thepressure and/or velocity adjustor configured to concentrate flow of thehumid gas-contaminated water vapor stream and to cause watercondensation, (0 the demister and condenser configured to collect watercondensed from the humid gas-contaminated water stream, while permittingthe remaining gas and waste vapor mixture to pass through, and (g) aclean water outlet configured to permit clean, condensed water from thenozzle-demister to flow to the clean water conduit, and (h) a fluidwaste outlet configured to remove the gas, gaseous waste, and liquidwaste from the nozzle demister.